Normally, pedicular screws joined by plates are implanted. However, this implantation depended on the spatial requirement of the holes of the plates, hence requiring a correct setting but small reduction.
Hooks are also implanted laid on the posterior arches moving around on rods with complex blocking systems. These systems allow for a correct setting and reduction but firstly require observance of the posterior vertebral arches and secondly delicate to-and-fro manoeuvres, dangerous for the patient and scarcely practical for the operator.